1. Field
The following description relates to a ballast type detecting technology. The following description also relates to a ballast type detecting circuit and a Light Emitting Diode (LED) lighting apparatus having the same for determining a type of a ballast to control a light apparatus, according to the type of the ballast.
2. Description of Related Art
Recently, a Light Emitting Diode (LED) is under consideration as a new lighting technology instead of a filament lamp or a fluorescent light. The LED may be driven in a low voltage, may have a longer lifetime, a lower power consumption, a faster response time and/or a stronger resistance when compared with other lighting apparatus types and may be implemented as a smaller size and a lighter weight apparatus. However, because the LED is operated using a low DC power and unlike a fluorescent light, the conventional LED may not be applied to a fluorescent light system. For example, when an LED drive circuit is directly coupled to a terminal of a conventional ballast, the LED drive circuit may not properly handle a high frequency or voltage of the ballast. As a result, such an LED may not be operate properly or may even explode.
Also, an output of an electronic ballast provides a pulse wave form having a high frequency and high voltage and an output of a magnetic ballast provides an AC input waveform having a low frequency. Because the electronic and magnetic ballasts may have different input characteristics and different control characteristics, it is desirable to have a circuit generating a selective signal according to a ballast type. A conventional ballast selection circuit is designed using an analog approach and needs many more outside elements, such as including an analog filter for frequency selection and a noise filter for noise elimination.